Motion-compensated optical coherence tomography system

Abstract

A motion-compensated optical coherence tomography system includes an optical coherence tomography sensor that includes a common-path optical fiber having an end for emitting light, reflecting reference light and receiving returned light for detection; a motion-compensation system attached to the common-path optical fiber and operable to move at least a portion of the optical fiber so as to compensate for motion between the end of the common-path optical fiber and an object being imaged; and a feedback control system configured to communicate with the optical coherence tomography sensor and the motion-compensation system. The feedback control system is configured to receive information concerning a measured distance of the end of the common-path optical fiber from the object and provide instructions to the motion-compensation system to decrease an amount of deviation of the measured distance from a desired distance.

We claim: 
     
       1. A motion-compensated optical coherence tomography system, comprising:
 an optical coherence tomography sensor comprising a common-path optical fiber having an end for emitting light, reflecting reference light and receiving returned light for detection; 
 a motion-compensation system attached to said common-path optical fiber and operable to move at least a portion of said optical fiber so as to compensate for motion between said end of said common-path optical fiber and an object being imaged; 
 a feedback control system configured to communicate with said optical coherence tomography sensor and said motion-compensation system; and 
 a data processing system in communication with said optical coherence tomography sensor; 
 wherein said feedback control system is configured to receive information concerning a measured distance of said end of said common-path optical fiber from said object and provide instructions to said motion-compensation system to decrease an amount of deviation of said measured distance from a desired distance, 
 wherein said motion-compensated optical coherence tomography system is configured to provide a two-dimensional image from said return light through said common-path optical fiber, 
 wherein said data processing system is configured to process detection signals from said optical coherence tomography sensor and generate said image, 
 wherein said motion-compensation system removes a surface topology of said object in said two-dimensional image, and 
 wherein said data processing system is configured to restore said surface topology of said object in said two-dimensional image. 
 
     
     
       2. A motion-compensated optical coherence tomography system according to  claim 1 , wherein said motion-compensation system comprises an inner needle and an outer needle, said inner needle being slideably disposed within said outer needle, and
 wherein said common-path optical fiber is disposed within said inner needle with said end of said common-path optical fiber being recessed within said inner needle to avoid contact with said object being imaged. 
 
     
     
       3. A motion-compensated optical coherence tomography system according to  claim 2 , wherein said motion-compensation system comprises a motor adapted to move said inner needle in an axial direction relative to said outer needle to thereby change a distance of said end of said common-path optical fiber from said object being imaged in response to said feedback control system. 
     
     
       4. A motion-compensated optical coherence tomography system according to  claim 3 , further comprising a hand piece housing at least a portion of said common-path optical fiber and said motor, and attached to or integral with said outer needle, such that said motion-compensated optical coherence tomography system is a free-hand scanning motion-compensated optical coherence tomography system. 
     
     
       5. A motion-compensated optical coherence tomography system according to  claim 1 , wherein said data processing system is configured to restore said surface topology by performing a topological correction of said detection signals. 
     
     
       6. A motion-compensated optical coherence tomography system according to  claim 5 , wherein said topological correction of said detection signals comprises maximizing a cross correlation between adjacent A-lines of an M-scan image to select a relative axial shift between said adjacent A-lines. 
     
     
       7. A motion-compensated optical coherence tomography system according to  claim 4 , wherein said data processing system is configured to restore said surface topology by performing a topological correction of said detection signals. 
     
     
       8. A motion-compensated optical coherence tomography system according to  claim 7 , wherein said topological correction of said detection signals comprises maximizing a cross correlation between adjacent A-lines of an M-scan image to select a relative axial shift between said adjacent A-lines. 
     
     
       9. A motion-compensated optical coherence tomography system according to  claim 4 , wherein said motor is a piezoelectric motor, and wherein said feedback control system is configured to control speed u m  of said piezoelectric motor to reduce error e=D-do between measured distance D and desired distance do according to the formula 
       
         
           
             
               
                 u 
                 m 
               
               = 
               
                 
                   
                     K 
                     P 
                   
                   ⁢ 
                   e 
                 
                 + 
                 
                   
                     K 
                     I 
                   
                   ⁢ 
                   
                     ∫ 
                     e 
                   
                 
                 + 
                 
                   
                     K 
                     D 
                   
                   ⁢ 
                   
                     ⅆ 
                     
                       ⅆ 
                       t 
                     
                   
                   ⁢ 
                   e 
                 
               
             
           
         
       
       where K P , K I  and K D  are proportional, integral and derivative gain coefficients, respectively. 
     
     
       10. A motion-compensated optical coherence tomography system according to  claim 9 , wherein said proportional, integral and derivative gain coefficients K P , K I  and K D  are empirically optimized. 
     
     
       11. A motion-compensated optical coherence tomography system according to  claim 8 , wherein said motor is a piezoelectric motor, and
 wherein said feedback control system is configured to control speed u m  of said piezoelectric motor to reduce error e=D−d 0  between measured distance D and desired distance do according to the formula 
 
       
         
           
             
               
                 u 
                 m 
               
               = 
               
                 
                   
                     K 
                     P 
                   
                   ⁢ 
                   e 
                 
                 + 
                 
                   
                     K 
                     I 
                   
                   ⁢ 
                   
                     ∫ 
                     e 
                   
                 
                 + 
                 
                   
                     K 
                     D 
                   
                   ⁢ 
                   
                     ⅆ 
                     
                       ⅆ 
                       t 
                     
                   
                   ⁢ 
                   e 
                 
               
             
           
         
          where K P , K I  and K D  are proportional, integral and derivative gain coefficients, respectively. 
       
     
     
       12. A motion-compensated optical coherence tomography system according to  claim 11 , wherein said proportional, integral and derivative gain coefficients K P , K I  and K D  are empirically optimized. 
     
     
       13. A motion-compensated optical coherence tomography system according to  claim 1 , wherein said optical coherence tomography sensor is a Fourier domain, common-path optical coherence tomography sensor. 
     
     
       14. A motion-compensated optical coherence tomography system according to  claim 12 , wherein said optical coherence tomography sensor is a Fourier domain, common-path optical coherence tomography sensor.